Effects Of Foliar Spraying 5-aminolevulinic Acid On Photosynthesis And Invertase Gene Expression In Grape

We studied the effects of different concentrations of 5-aminolevulinic acid on the leaf photosynthesis,fruit quality in grape.Grape invertase gene response to ALA was also analyzed.Provide theoretical basis for the application of exogenous 5-aminolevulinic acid in grape cultivation.The grape invertase genes were identified and analyzed their expression profiles.The main results were as follows:1.Different concentrations of ALA increased the content of leaf chlorophyll a and carotenoids.After 10、25、50 mg/L ALA treatments,the leaf net photosynthetic rate increased 50%,79%,and 65%,respectively.After 25 and 50 mg/L ALA treatments,the transpiration rates increased 147% and 96%,and the stomatal conductance increased 165% and 110%,respectively.According to the chlorophyll fluorescence assay,ALA treatment had an inhibitory effect on leaf dark-adapted initial fluorescence,but lesf photochemical fluorescence quenching coefficient was enhancement.ALA has also enhanced leaf electron transfer rate and actual photochemical efficiency.ALA treatments also increased the activities of antioxidant enzymes such as leaf SOD,CAT,and POD.The activities of SOD increased 94.5% and 57.6% after treatment with 25 and 50 mg/L ALA,respectively.The activities of POD were 2.2 times higher than that of the control after 25 mg/LALA treatment.After 10 and 25 mg/L ALA treatments,the activities of CAT increased 81.5% and 102.2%,respectively.2.After foliar spraying ALA,the fruit quality of Crimson seedless was significantly increased.ALA slightly increased the fruit grain weight.ALA significantly increased fruit vertical diameters,soluble solids content,sugar-acid ratio and horizontal.After 25 mg/L ALA treatment,the fruit grain weight,soluble solids content and sugar-acid ratio increased 5.7%,41.4% and 63.1%,respectively.After treatment with ALA,Crimson’s coloration rate was significantly improved.And the analysis of the fruit surface color index shows that ALA treatment is conducive to the coloration of fruit.The analysis of the grape invertase genes response to ALA showed that most grape invertase genes were induced by ALA except VvNI3,Vv NI5 b and Vv NI6.3.We identified 19 grape invertase genes in gape genome,including 5 cell wall invertase genes,3 vacuolar invertase genes,and 11 neutral/alkaline invertase genes.These genes located on 11 diffrent chromosomes.The tissue expression patterns of invertase genes were analyzed by qRT-PCR.Results of qRT-PCR show that Vv CWINV1、VvCWINV2、Vv CWINV3 were highly expressed in roots,VvVINV1、VvCWINV5、VvNI5a and VvNI5 b have higher expression levels in flower buds.VvNI9 was only expressed inflower buds.VvVINV2、Vv VINV3、VvNI1、VvNI2 and VvNI7 have higher expression levels in stems.VvVINV1 has higher expression levels in stems and ovules。VvVINV6 was expressed in 9 tissues.The expression level of VvCWINV2、VvVINV1、VvVINV2、VvVINV3、VvNI4、VvNI5b and VvNI7 was generally higher in Thompson Seedless ovules than in Pinot Noir ovules.The expression level of VvCWINV1 and VvNI2 were generally higher in Pinot Noir ovules than Thompson Seedless ovules.The response analysis of grape invertase gene to hormones of ABA,Et H and MeJA showed that VvVINV1,VvVINV3,VvCWINV4,VvCWINV5,VvNI3 and VvNI5 a were induced by MEJA;VvCWINV2 was up-regulated by ETH;VvCWINV3 and VvNI6 were induced by ABA.